Shared integrated DC-DC supply regulator

ABSTRACT

The systems and processes described herein can reduce the footprint of the internal devices of a wireless device by combining the DC-DC supply regulator with a FEM. Further, the device footprint can be further reduced by sharing the integrated DC-DC supply regulator among multiple FEMs reducing or eliminating the use of a separate DC-DC supply regulator for each FEM of a wireless device. Moreover, in certain embodiments, by integrating the DC-DC supply regulator into a 2G FEM, power efficiency can be improved for some wireless devices. For example, the DC-DC supply regulator may be used to supply power to a PA used for high-band 2G transmission functions. Using the DC-DC supply regulator can improve power efficiency compared to systems that supply the power for the high-band 2G PA directly from the power supply (e.g., the battery).

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/868,949, which was filed on Sep. 29, 2015 and is titled “SHAREDINTEGRATED DC-DC SUPPLY REGULATOR,” the disclosure of which is expresslyincorporated by reference herein in its entirety, and which claimspriority to U.S. Provisional Application No. 62/057,467, which was filedon Sep. 30, 2014 and is titled “SHARED INTEGRATED DC-DC SUPPLYREGULATOR,” the disclosure of which is expressly incorporated byreference herein in its entirety.

BACKGROUND Technical Field

The disclosed technology relates to DC-DC supply regulators and, inparticular, to DC-to-DC supply regulators for supporting power amplifieroperation.

Description of Related Technology

One type of device that converts one direct current (“DC”) voltage levelto another DC voltage level may be referred to as a DC-to-DC supplyregulator or DC-to-DC converter (DC-DC converter). DC-DC converters canbe included in battery-operated devices such as mobile telephones,laptop computers, etc., in which the various subsystems of the devicerequire several discrete voltage levels. In some types of devices, suchas a mobile telephone that operates in a number of different modes, itcan be desirable to supply certain elements, such as power amplifiers,with a supply voltage at a more efficient level for the mode ofoperation, rather than waste power and accordingly drain the batteryprematurely. In such devices, it can be desirable to employ a DC-DCconverter that can generate a number of discrete voltage levels.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers are re-used to indicatecorrespondence between referenced elements. The drawings are provided toillustrate embodiments of the inventive subject matter described hereinand not to limit the scope thereof.

FIG. 1A illustrates a block diagram of an embodiment of a wirelessdevice with a number of front-end modules that are each associated witha separate DC-DC supply regulator.

FIG. 1B illustrates a block diagram of an embodiment of a wirelessdevice with a number of front-end modules that share an integrated DC-DCsupply regulator.

FIG. 2 illustrates a block diagram of an embodiment of a portion of amulti-chip module that includes a pair of front-end modules with ashared integrated DC-DC supply regulator.

FIG. 3 illustrates a block diagram of an embodiment of a layout of a 2Gfront-end module with a shared integrated DC-DC supply regulator.

FIG. 4 illustrates a portion of a circuit diagram for a front-end modulewith an integrated DC-DC supply regulator and power amplifier biascircuit.

FIG. 5 illustrates a block diagram of a wireless device including anumber of front-end modules.

FIG. 6 illustrates a block diagram of a wireless device including anumber of front-end modules that share a DC-DC supply regulatorintegrated in a 3G front-end module.

SUMMARY

One aspect of this disclosure relates to a front-end module (FEM) of awireless device. The FEM may include a first power amplifier and anintegrated DC-DC supply regulator. The integrated DC-DC supply regulatormay regulate a first supply voltage provided to the first poweramplifier. Further, the integrated DC-DC supply regulator may regulate asecond supply voltage provided to a second power amplifier that isexternal to the FEM.

In certain embodiments, the second power amplifier is included in adifferent FEM. The FEM may be configured for 2G communication. However,in some cases, the different FEM that includes the second poweramplifier may be configured for non-2G communication.

Further, the FEM may include a switch configured to supply a signal fromone of the first power amplifier and the second power amplifier to anantenna. In addition, the FEM may include a third power amplifier thatis configured to provide low band 2G communication. In contrast, thefirst power amplifier may be configured to provide high band 2Gcommunication. In some cases, the third power amplifier receives a thirdsupply voltage from a power source. This third supply voltage may bereceived directly, or indirectly, from the power source instead of fromthe integrated DC-DC supply regulator.

In some implementations, the integrated DC-DC supply regulator regulatesthe first supply voltage and the second supply voltage based on avoltage received from a power source. Further, the integrated DC-DCsupply regulator may be combined with a bias circuit. This bias circuitcan supply a bias current to the first power amplifier. Moreover, theintegrated DC-DC supply regulator can include a capacitor and aninductor that are external to the FEM. Thus, in certain embodiments, theintegrated DC-DC supply regulator may be partially integrated with theFEM and partially external to the FEM. With some implementations, theFEM may further include one or more impedance matching networksconfigured to match an impedance value of the first power amplifier toan impedance value of an antenna.

Another aspect of this disclosure relates to a multi-chip module (MCM).The MCM may include a first front-end module (FEM) that can include afirst power amplifier and an integrated DC-DC supply regulatorconfigured to regulate a first supply voltage provided to the firstpower amplifier. Further, the MCM may include a second FEM that caninclude a second power amplifier. The second power amplifier may beconfigured to receive a second supply voltage from the integrated DC-DCsupply regulator.

In some embodiments, the first FEM is configured for 2G communicationand the second FEM is configured for non-2G communication. In addition,the first FEM may further include a switch configured to supply a signalfrom one of the first power amplifier and the second power amplifier toan antenna. Moreover, the first FEM may include a third power amplifier.In some such cases, the first power amplifier may be configured toprovide high band 2G communication and the third power amplifier may beconfigured to provide low band 2G communication. Furthermore, the thirdpower amplifier may receive a supply voltage from a source other thanthe integrated DC-DC supply regulator.

In some designs, the integrated DC-DC supply regulator may regulate thefirst supply voltage and the second supply voltage based on a voltagereceived from a power source. Further, the integrated DC-DC supplyregulator may be combined with a bias circuit. This bias circuit may beconfigured to supply a bias current to the first power amplifier. Inaddition, the MCM may further include a capacitor and an inductorexternal to the first FEM. The capacitor and the inductor may both bepart of the integrated DC-DC supply regulator of the first FEM.

In yet another aspect of this disclosure, a wireless device isdisclosed. The wireless device may include an antenna configured toprovide a signal and/or receive a signal from a multi-chip module (MCM).Further, the wireless device may include the MCM. This MCM may include afirst front-end module (FEM) and a second FEM. The first FEM may includea first power amplifier and an integrated DC-DC supply regulatorconfigured to regulate a first supply voltage provided to the firstpower amplifier. The second FEM may include a second power amplifierthat may be configured to receive a second supply voltage from theintegrated DC-DC supply regulator.

In some cases, the first FEM is configured for 2G communication and thesecond FEM is configured for non-2G communication. In addition, thefirst FEM may further include a switch configured to supply a signalfrom one of the first power amplifier and the second power amplifier tothe antenna. Further, the first FEM may include a third power amplifier.The first power amplifier may be configured to provide high band 2Gcommunication and the third power amplifier may be configured to providelow band 2G communication. Moreover, the third power amplifier canreceive a supply voltage from a source other than the integrated DC-DCsupply regulator.

The wireless device may further include a power source and theintegrated DC-DC supply regulator may be further configured to regulatethe first supply voltage and the second supply voltage based on avoltage received from the power source. Further, the integrated DC-DCsupply regulator may be combined with a bias circuit. This bias circuitmay be configured to supply a bias current to the first power amplifier.In addition, the MCM may further include a capacitor and an inductorthat is external to the first FEM. This capacitor and the inductor maybe part of the integrated DC-DC supply regulator of the first FEM.

DETAILED DESCRIPTION

Typically, an electronic device will include a number of poweramplifiers. Wireless devices are no exception. Often, a wireless devicewill include a number of power amplifiers that are included in one ormore front-end modules (FEMs). Further, the wireless device may includeone or more additional components that support the power amplifier. Forexample, the wireless device will often include a number of matchingcircuits that match various elements of the FEM to an impedance of theantenna, which is typically designed to be 50 Ohms. As a second example,the wireless device may include a number of bias circuits for biasingthe power amplifiers. As a third example, the wireless device mayinclude one or more DC-DC supply regulators for modifying a voltagelevel and/or current level supplied to a power amplifier.

Each of the various components described in the previous paragraph addto the size of the wireless device. There is typically an inherenttension between including additional features in a wireless device andreducing the size and weight of the wireless device. This inherenttension is exacerbated by the desire to extend battery life withoutincreasing the size of the battery, which typically accounts for asignificant percentage of the weight of the wireless device.

Advantageously, embodiments described herein eliminate die content,resulting in a smaller device footprint, while maintaining or increasingpower efficiency. The systems and processes described herein can reducethe footprint of the internal devices of a wireless device by combiningthe DC-DC supply regulator with a FEM. Further, the device footprint canbe further reduced by sharing the integrated DC-DC supply regulatoramong multiple FEMs reducing or eliminating the use of a separate DC-DCsupply regulator for each FEM of a wireless device. Moreover, in certainembodiments, by integrating the DC-DC supply regulator into a 2G FEM,power efficiency can be improved for some wireless devices. For example,the DC-DC supply regulator may be used to supply power to a PA used forhigh-band 2G transmission functions. Using the DC-DC supply regulatorcan improve power efficiency compared to systems that supply the powerfor the high-band 2G PA directly from the power supply (e.g., thebattery).

Example Wireless Device

FIG. 1A illustrates a block diagram of an embodiment of a simplifiedwireless device 100 with a number of front-end modules 102 that eachelectrically communicate with a DC-DC supply regulator 110, which mayalso be referred to as a DC-DC converter circuit. The front-end modules102 can include a number of FEMs for facilitating signal transmissionacross a set of communication bands using a number of communicationsstandards or technologies. Often, the communication standards ortechnologies are identified by generation or version. For example, alarge percentage of the world uses second generation wireless telephonetechnology for transmitting voice calls. This technology is typicallyreferred to as 2G or 2-G. Other communications standards include 2.5G,3G, 4G, 4G LTE, 5G, WiMAX, GSM, CDMA, etc.

As illustrated in FIG. 1A, the front-end modules 102 may include a 2GFEM 104, a 3G FEM 106, and a 4G FEM 108. Each of the FEMs 102 mayfacilitate transmission of a communications signal via the antenna 122.Further, at least some of the FEMs 102 may transmit using a differenttechnology and/or over a different frequency band. The FEMs 102 may eachreceive power from a DC-DC supply regulator 110. For example, the 2G FEM104 may receive power from the DC-DC supply regulator 110A, the 3G FEM106 may receive power from the DC-DC supply regulator 110B, and the 4GFEM 108 may receive power from the DC-DC supply regulator 110C. Tosimplify discussion, and not to limit the disclosure, the DC-DC supplyregulators 110A, 110B, and 110C may be referred to as a DC-DC supplyregulator 110, in the singular or the plural. In some embodiments, theDC-DC supply regulator 110A may be omitted. In such embodiments, the 2GFEM 104 may receive power directly from a power source (e.g., abattery).

Typically, as illustrated in FIG. 1A, each FEM 102 may be powered by itsown DC-DC supply regulator 110. Further, although not shown, each DC-DCsupply regulator 110 may be in electrical communication with its owninductor and capacitor. Thus, the more wireless technologies orstandards that may be supported by a given wireless device, the morespace that may be allocated to DC-DC supply regulators 110.

Further, in some embodiments, one or more of the FEMs, such as the 2GFEM 104, may support multiple bands. For instance, the 2G FEM 104 maysupport a low band and a high band mode. Often, the low band supportingdevices (e.g., a low band PA) in the 2G FEM 104 are powered directly bythe battery, or other power supply. Although the high band supportingdevices (e.g., a high band PA) may be powered via a DC-DC supplyregulator, often the die that includes the 2G FEM includes a singlesupply pin. Thus, in such cases, the high band supporting devices arealso powered directly by the power supply, which can result in a reducedpower efficiency compared to a system that enables the high bandsupporting devices to be powered via the DC-DC supply regulator 110A.

As discussed in more detail below, embodiments disclosed herein reducethe footprint of the wireless communication system by integrating theDC-DC supply regulator within an FEM and sharing the integrated DC-DCsupply regulator between the FEMs of the wireless device, as illustratedin FIG. 1B. Further, in some embodiments, by integrating the DC-DCsupply regulator into an FEM that supports multiple bands, powerefficiency can be improved by enabling high band (e.g., 1800-1900 MHz)supporting components to be powered via the DC-DC supply regulator whilelow band (e.g., 800-900 MHz) supporting components are powered directlyby the power supply (e.g., a battery).

FIG. 1B illustrates a block diagram of an embodiment of a wirelessdevice 150 with a number of front-end modules 120 that share anintegrated DC-DC supply regulator 142. As with the wireless device 100,the FEMs 120 of the wireless device 150 can include multiples FEMs. Forinstance, the illustrated example includes 2G FEM 140, 3G FEM 106, 4GFEM 108. However, unlike the FEMs 102 of FIG. 1A, the FEMs 120 share aDC-DC supply regulator 142, which can be integrated into the 2G FEM 140.

Although the DC-DC supply regulator 142 is integrated into the 2G FEM140 in the illustrated example, it should be understood that the DC-DCsupply regulator could alternatively be integrated into a different FEM,such as the 3G FEM 106. Further, although the wireless device 150includes one DC-DC supply regulator 142 that is shared among each of theFEMs 120, it should be understood that the FEMs 120 can include multipleDC-DC supply regulators with at least one of the DC-DC supply regulatorsbeing shared among at least two FEMs. For instance, the 2G FEM 140 mayinclude its own DC-DC supply regulator, while the 3G FEM 106 may includea separate DC-DC supply regulator that it shares with the 4G FEM 108.

Example Multi-Chip Module

FIG. 2 illustrates a block diagram of an embodiment of a portion of amulti-chip module 200 (MCM) that includes a pair of front-end moduleswith a shared integrated DC-DC supply regulator. The MCM 200 may beincluded as part of a communications system of a device, which may be awired or wireless device. It should be understood that the MCM 200 mayinclude a number of additional devices, such as a power amplifiercontroller and one or more additional filters. However, to simplifydiscussion and not to limit the disclosure, these additional componentshave been omitted from FIG. 2.

The MCM 200 may include a FEM 210 and an FEM 230. Although two FEMs aredepicted, it is possible for the MCM 200 to include more or fewer FEMs.In some embodiments, the MCM 200 may include a separate FEM for eachcommunications technology supported by a device that includes the MCM200. In the illustrated example of FIG. 2, the FEM 210 represents a 2GFEM that supports a 2G communications standard. The FEM 230 may beconfigured to support one or more alternative communications standardsor technologies. For example, the FEM 230 may be configured to support3G and 4G communications. Further, the FEM 230 may support a number ofcommunications bands. For example, the FEM 230 may support six or sevencommunications bands. In the illustrated example, the FEM 230 supports anumber of communications bands via the three power amplifiers 232A,232B, 232C, which may individually or collectively be referred to aspower amplifiers 232. In some cases, each power amplifier 232 supports adifferent communication band. Alternatively, at least some of the poweramplifiers 232 may support multiple communication bands. Thus, althoughthe FEM 230 includes three power amplifiers 232, the FEM 230 may supportmore than three communication bands.

The FEM 210 includes a combined DC-DC supply regulator (or converter)and bias circuit block 216. To simplify discussion, and not to limit thedisclosure, the combined DC-DC supply regulator and bias circuit block216 will be referred to herein as a DC-DC+ bias 216. The DC-DC+ bias 216can provide both the functionality of a DC-DC supply regulator and abias circuit. Advantageously, in certain embodiments, the DC-DC+ bias216 can be integrated into the FEM 210 with minimal increase in the sizeof the 2G FEM. In some cases, the die incorporating the DC-DC supplyregulator increases in size by less than 20% when the DC-DC supplyregulator and bias circuit are combined. This size increase of theDC-DC+ bias die may translate to less than a 5% increase in the size ofthe 2G FEM. In some cases, the discrepancy in the size increase of theDC-DC die is because, in some cases, the inductor and capacitor may beexternal to the 2G FEM. Further, although the 2G FEM may increase by asmall percentage in size, the overall size of the wireless device may bereduced because other FEMs may share the DC-DC supply regulator with the2G FEM. Moreover, in some embodiments, the DC-DC+ bias 216 can beintegrated into the FEM 210 without increasing the size of the 2G FEM.Moreover, in some implementations, the DC-DC+ bias 216 can be integratedinto a 3G or other FEM with little to no increase in the size of theFEM.

Advantageously, by integrating the DC-DC supply regulator with the biascircuit in the FEM 210, the size of the footprint required for the 2Gcommunications circuitry may be reduced. Further, in someimplementations, power efficiency may be increased because, for example,power may be supplied to the high band PA 212 by the DC-DC+ bias 216.The DC-DC+ bias 216 can regulate the supplied power to improve the powerefficiency of the high band PA 212. Further, as the low band PA of the2G FEM typically draws a significant amount of current, the low band PA214 may be powered directly by the battery 204, or other power source,by placing the lower band PA 214 in electrical communication with thebattery without the DC-DC supply regulator.

As illustrated in FIG. 2, the MCM 200 further includes an inductor 226and a capacitor 228. The inductor 226 and the capacitor 228, althoughexternal to the FEM 210, may form part of the DC-DC+ bias 216. Thus, theinductor 226 may be referred to as a DC-DC inductor and the capacitor228 may be referred to as a DC-DC capacitor. The inductor 226 and thecapacitor 228 facilitate the conversion of power from the DC-DC supplyregulator of the DC-DC+ bias 216. Further, as illustrated by the Vccinput 206, the DC-DC+ bias 216 provides power to the FEM 230. Thus,advantageously, the integrated DC-DC+ bias 216 of the FEM 210 can beused to power the FEM 230 thereby eliminating a separate DC-DC supplyregulator for the FEM 230 and further reducing the footprint of the MCM200.

As previously indicated, the FEM 210 includes a power amplifier 212 anda power amplifier 214. The power amplifier 212 can be configured tosupport high band 2G operation (e.g., 1800-1900 MHz) and the poweramplifier 214 can be configured to support low band 2G operation (e.g.,800-900 MHz). Further, each of the power amplifiers 212, 214 may supportmultiple communication bands. Although not limited as such, both thepower amplifier 212 and the power amplifier 214 may be formed from a setof heterojunction bipolar transistors (HBTs). Similarly, the poweramplifiers 232 of the FEM 230 may be formed from a set of HBTs.

The FEM 210 further includes an impedance matching 218 and an impedancematching circuit 220 configured to match the impedance at the output ofthe power amplifier 212 and the power amplifier 214, respectively, to animpedance of the antenna 224. Typically, the antenna 224 is designed tobe at a 50 Ohm impedance. However, it is possible for the antenna 224 tobe designed for a different impedance value. Further, in some cases, theimpedance of the antenna 224 may vary based on the operation of thewireless device that includes the MCM 200. For instance, the impedancemay change based on the distance of the wireless device to a basestation or the location of the user's hand in relation to the antenna224. In such cases, the impedance matching circuits 218 and 220 may beconfigured to adjust the impedance at the output of the power amplifier212 and 214, respectively, based on the measured impedance at theantenna 224.

In addition, the FEM 210 includes a switch 222 that is configured todetermine which signal should be sourced or provided to the antenna 224.As illustrated in FIG. 2, the switch 222 can receive signals from theFEM 230, via the duplexers 234, as well as from the PAs 212 and 214, viathe respective impedance matching circuits 218 and 220. The switch 222can provide a selected signal to the antenna 224 based on a controlsignal. In some embodiments, the control signal may be provided by theDCDC+ bias 216.

As indicated above, the MCM includes a number of duplexers 234. In somecases, a duplexer 234 may exist for each PA 232 in the FEM 230. Forinstance, the duplexer 234A may correspond to the PA 232A, the duplexer234B may correspond to the PA 232B, and the duplexer 234B may correspondto the PA 232B. In some cases, one or more of the duplexers 234 may beshared by one or more of the PAs 232. Further, the duplexers 234 mayinclude one or more filters for filtering the output of the FEM 230.

The power amplifiers of the MCM 200 can include any type of poweramplifier. Further, the power amplifiers may be set to operate at aparticular operating point. This operating point may be configured bythe DCDC+ bias 216, which may provide a bias current and/or voltage toone or more of the power amplifiers. In some embodiments, the FEM 230may include a separate bias circuit for the PAs 232 of the FEM 230.

Although much of the above discussion has been in the context oftransmitting a signal, it should be understood that the FEMs 210 and 230may also be involved in receiving a signal from the antenna 224. Forinstance, the duplexers 234 may also provide a received signal to atransceiver within a wireless device.

Example Layout of a 2G FEM

FIG. 3 illustrates a block diagram of an embodiment of a block layout300 of a 2G front-end module 210 with a shared integrated DC-DC supplyregulator 216. In the example illustrated in FIG. 3, the high band PA212 and the low band PA 214 of FIG. 2 are included in a single block asa multiband PA 310. In addition, the FEM 210 includes a pair ofadditional impedance matching blocks, antenna impedance matching block302 and interstage impedance matching block 304.

The antenna impedance matching block 302 may include a circuit formatching the impedance between the antenna 224 and the switch 222.Further, the antenna impedance matching block 302 may be configured tomatch the impedance both when signals are being transmitted andreceived. In addition, in some embodiments, the antenna impedancematching block 302 is configured to generate a harmonic match and/or tofilter out particular harmonics of the transmit or receive signal.Moreover, the antenna impedance matching block 302 may be configured toprotect against electrostatic damage (ESD) that may occur, for example,from human contact with the antenna 224.

The interstage impedance matching block 304 is configured to performimpedance matching between the stages of the power amplifiers of themultiband PA 310. Typically, although not necessarily, the poweramplifiers of the multiband PA 310 will include multiple stages, whicheach contribute to the gain factor of the PAs. Usually, a lower powerinput is applied to the input of the PA and the PA outputs a signal at ahigher power. The applied gain can result in an impedance mismatchbetween stages of the PA. The interstage impedance matching block 304can match the impedance between the lower power input stage, the one ormore intermediate stages, and the output stage of the PAs included inthe multiband PA 310.

The block layout 300 includes a second FEM 330, which is configured toprovide a communications band, such as LTE-band 1, other than the 2Gbands of the FEM 210. The FEM 330 includes a B1 PA 332 configured toprovide gain for the communication signal transmitted or received viathe FEM 330. Further, the signal output by the B1 PA 332 is provided toa duplexer 334, which can include one or more filters for the receivedsignal or the signal to be transmitted via the antenna 224.

Example FEM Circuit that Includes an Integrated DC-DC Supply Regulator

FIG. 4 illustrates a portion of a circuit diagram for a front-end module410 with an integrated DC-DC supply regulator (or converter)+ bias block216 that includes a power amplifier bias circuit 402. The integratedDC-DC supply regulator 216 includes a DC-DC supply regulator 402 inaddition to the power amplifier bias circuit 404. The front-end module410 may include some or all of the features and components illustratedand described with respect to the FEM 210. These additional features andcomponents have been omitted from the FEM 410 to simplify the diagramand not to further limit the design.

The FEM 410 is a 2G FEM that supports multiple frequency bands with theinclusion of multiple power amplifiers. Although FIG. 4 illustrates a 2GFEM, certain embodiments of the FEM 410 may also be applicable for FEMsthat support other communication technologies, such as 3G, 4G LTE, or5G. The FEM 410 may include a low band (or LB) PA 214 and a high band(or HB) PA 212. In some embodiments, the HB PA 212 may also support midband (or MB) operation.

Both the LB PA 214 and the HB PA 212 are illustrated as three-stage PAs.However, the power amplifiers are not limited as such and may includefewer stages, such as two stages, or a greater number of stages, such asfour stages or any other number of stages. Typically, the low band PA214 tends to have a higher upper power requirement compared to the HB PA212. For example, in some cases, the upper power requirement of the LBPA 214 can be up to 3 dB higher than that of the HB PA 212. Thus, asillustrated in FIG. 4, each stage of the LB PA 214 is supplied its powerby the power supply input (e.g., Vbatt) to the FEM 410. This isillustrated in FIG. 4 by the line that connects the Vbatt to the outputof each transistor stage 214A, 214 b, and 214 c in the LB PA 214. Incontrast, while the first two stages 212 a and 212 b of the HB PA 212receive power directly from Vbatt, the output stage 212 c can draw itspower from the output of the DCDC+ bias 216. In some cases, the voltagesupplied by the Vbatt may be about 3.8 volts. However, in certainimplementations, the Vbatt may have a different voltage value or voltagerange.

The bias circuit 404 of the DC-DC+ bias 216 can supply a referencecurrent to bias each transistor of the amplifiers that make up the HBand/or MB PA 212 and the LB PA 214. This bias circuit 404 may beintegrated onto the same die as the DC-DC supply regulator 402, whichtogether forms the DC-DC+ bias 216. This DC-DC+ bias 216 may itself becombined with other features, such as a PA, of the FEM 410 on a singledie or may be a separate die that is included as part of the FEM 410.

As illustrated, the bias circuit 404 may receive a reference voltageVref1. This reference voltage may be an external analog voltage providedto the system by, for example, a cellular radio, or may be generated byan integrated data converter that generates the reference voltage basedon a digital interface. The reference voltage Vref1 may be provided toan operational amplifier in a feedback loop with a first transistor T1,which creates a voltage to current converter. The current may then besupplied by the transistors T2, T3, and T4 to the transistor stages ofthe PAs. For instance, the transistor T2 may supply the bias current tothe first stage 212 a and 214 a of the PAs 212 and 214, respectively.Similarly, the transistor T3 may supply the bias current to the secondstage 212 b and 214 b of the PAs 212 and 214, respectively, and thetransistor T4 may supply the bias current to the output stage 212 c and214 c of the PAs 212 and 214, respectively. One or more of thetransistors T1, T2, T3, and T4 may be pFETs. However, the transistorsare not limited as such and may include other types of transistors, suchas nFETs, BJTs, or HBTs.

In certain embodiments, one or more of the transistors T2, T3, and T4may supply a different current to one or more of the respectivetransistor stages of one or more of the PAs 212 and 214. For example,the transistor T4 may supply a larger bias current to the output stages212 c and 214 c than the transistor T2 may supply to the input stages212 a and 214 a of the PAs 212 and 214. In some cases, the bias currentsupplied to one stage of the PAs 212 and 214 may be a multiple of thebias current supplied to another stage. For instance, the output stagesof the PAs 212 and 214 may receive three time the bias current of theinput stages to the PAs 212 and 214. Moreover, in certain embodiments,one or more stages of the PA 212 may receive a different bias currentthan the corresponding stage from the PA 214. In other words, the firststage 212 a may receive a different bias current than the first stage214 a.

The DC-DC supply regulator 402 integrated into the FEM 410, which can bea 2G FEM, may supply power to PAs that are external to the FEM 410, suchas to one or more PAs that support 3G or 4G operation by a wirelessdevice. This provisioning of power to external devices is illustratedthe “To 3G/4G” output of the FEM 410. Although the output line addresses3G or 4G, it should be understood that the disclosure is not limited assuch and that the DC-DC supply regulator 402 of the FEM 410 may supplypower to PAs that support other types of wireless operation, such as 5G.Advantageously, the design of FIG. 4 enables multiple PAs supportingdifferent wireless communication standards and/or frequency bands toshare a single DC-DC supply regulator 402, which may result in cheaperand smaller devices because, for instance, the number of DC-DC supplyregulators for a wireless device may be reduced.

Generally, each stage of a high band PA included in a 2G supporting FEMis supplied power by Vbatt. This is often the case because the low bandPA due to its relatively high power requirements needs to draw its powerfrom Vbatt. As illustrated in FIG. 4, by integrating the DC-DC supplyregulator 402 into the FEM 410, the output stage 212 c of the HB PA 212can draw power from the DC-DC supply regulator 402. Typically, theoutput stage 212 c may be supplied the same power that is output to the3G/4G (or other supported communication technologies) power amplifiers.By supplying power to the HB PA 212 from the DC-DC supply regulator 402instead of from Vbatt, as may occur in certain other FEMs, theefficiency of the HB PA 212 can be improved.

As with the bias circuit 404, the DC-DC supply regulator 402 may receivea reference voltage Vref2. Generally, the reference voltage Vref2 is aseparate reference voltage from the reference voltage Vref1 received bythe bias circuit 404. However, in certain embodiments, although theVref1 and Vref2 voltages may be separate reference voltages receivedfrom separate sources, they may share the same voltage value. Moreover,in some embodiments, both the Vref1 and Vref2 may be received from thesame source. In some such cases, the Vref1 and Vref2 may be received atthe same pin of the FEM 410.

The reference voltage Vref2 received at the DC-DC supply regulator 402may be used to configure the supply voltage received by the DC-DC supplyregulator 402. Typically, this reference voltage Vref2 is independentfrom the bias circuit 404 and is not involved in configuring orproviding a bias current to the PAs 212 and 214.

In addition to the reference voltage Vref2, the DC-DC supply regulator402 receives a clock signal 420. As illustrated in FIG. 4, this clocksignal 420 may be a saw tooth signal. Further, the clock signal 420 maybe a pulse width modulated signal. The clock signal 420 may createshorter or longer pulses based on the current DC level. These pulsewidths will effectively turn on and off the switches represented by thetransistors 422 and 424 for different durations to vary the voltage thatis output from the DC-DC supply regulator 402 across the inductor 426.As previously described, the output signal may be provided to otherFEMs, such as a 3G or 4G FEM, and/or to the output stage of the HB PA212 of the FEM 410. Further, the varying pulse widths of the clocksignal 420 may alter the duty cycle of the DC-DC supply regulator 402,which can result in the output voltage being adjusted to bring it closerto the target voltage which may be determined based at least in part onthe reference voltage Vref2.

The inverter 430 can provide a control signal to the transistors 422 and424 that may be based on the received reference signal Vref2 and theclock signal 420. Based on this control signal, the transistors 422 and424 can be turned on or off, thereby switching the inductor 426 betweenVbatt and ground.

In certain cases, the target voltage may be at or near the Vbattvoltage. When these cases occur, it can be inefficient to use the DC-DCsupply regulator 402 to adjust the voltage output by the FEM 410 totrying and satisfy the desired target voltage. Thus, in some such cases,the DC-DC supply regulator 402, or its functionality, may bedeactivated, and the Vbatt may be supplied or shorted via a bypasstransistor 432 to the output through the inductor 426. Advantageously,in certain embodiments, by providing Vbatt to the output via theinductor 426 when the target voltage is close (e.g., within a thresholdvoltage difference) to the Vbatt, the energy required to operate theDC-DC supply regulator 402 functionality may be reduced therebyincreasing battery life for a wireless device that incorporates theDC-DC supply regulator 402.

Additional Wireless Device Examples

FIG. 5 illustrates a block diagram of a wireless device 500 includingmulti-chip module 550 with a number of front-end modules 540. Themulti-chip module 550 can include the MCM 200. Further, the MCM 550 caninclude one or more of the embodiments described above with respect tothe MCM 200 and/or the block layout 300.

In the example illustrated in FIG. 5, the FEMs 540 includes three FEMs,a 2G FEM 210, a 3G FEM 544, and a 4G FEM 546. In some implementations,one or more of the FEMs may be combined. For example, the 3G FEM 544 andthe 4G FEM 546 may be combined into a single FEM 230 as illustrated inFIG. 2. Further, the FEMs 540 may include more or fewer FEMs thanillustrated. As previously described, the 2G FEM 210 can include a DC-DCsupply regulator, which may be integrated with the bias circuit of the2G FEM. This DC-DC supply regulator may be shared with the 3G FEM 544and the 4G FEM 546 thereby enabling a reduction in the size of the FEMs540.

In addition to the FEMs 540, the MCM 550 may include a number ofadditional systems configured to facilitate operation of the PAsincluded in the FEMs 540. For example, the MCM 550 may include a PAcontroller 552 configured to set the mode of one or more PAs included inthe FEMs 540. Further, the PA controller 552 may configure the switch222 of the 2G FEM 210 to select a signal for transmission from one ofthe FEMs 540 or from a particular band supported by one of the FEMs 540,such as a low band transmission by the 2G FEM 210 or a 4G signal fromthe 4G FEM 546.

In some embodiments, the PA controller 552 may set the operating pointfor a PA included in a FEM 540 by modifying a bias circuit, such as theDCDC+ bias 216. For instance, the PA controller 552 may set or modify abias current provided by the DCDC+ bias 216 to the PA 212 of FIG. 2.

In addition, the MCM 550 may include one or more impedance matchingnetworks 554 configured to match one or more impedance values betweenone or more circuits in a load line. For instance, the impedancematching network 554 may be configured to match an impedance between theantenna 522A and the FEMs 540.

In some cases, the MCM 550 can receive RF signals from a transceiver 510that can be configured and operated in known manners to generate RFsignals to be amplified and transmitted, and to process receivedsignals. The transceiver 510 is shown to interact with a basebandsubsystem 508 that is configured to provide conversion between dataand/or voice signals suitable for a user and RF signals suitable for thetransceiver 510. The transceiver 510 may also be connected to a powermanagement component 506 that is configured to manage power for theoperation of the wireless device. Such power management can also controloperations of the baseband sub-system 508 and the MCM 550. It shouldalso be understood that the power management component 506 may include apower supply, such as a battery. Alternatively, or in addition, one ormore batteries may be separate components within the wireless device500.

Other connections between the various components of the wireless device500 are possible, and are omitted from FIG. 5 for clarity ofillustration only and not to limit the disclosure. For example, thepower management component 506 may be electrically connected to thebaseband subsystem 508, the MCM 550, the DSP 512, or other components514. As a second example, the baseband subsystem 508 may be connected toa user interface processor 516 that may facilitate input and output ofvoice and/or data provided to and received from the user. The basebandsub-system 508 can also be connected to a memory 518 that may beconfigured to store data and/or instructions to facilitate the operationof the wireless device 500, and/or to provide storage of information forthe user.

In addition to the aforementioned components, the wireless device mayinclude one or more central processors 520. Each central processor 520may include one or more processor cores. Further, the wireless device500 may include one or more antennas 522A, 522B. In some cases, one ormore of the antennas of the wireless device 500 may be configured totransmit and receive at different frequencies or within differentfrequency ranges. Further, one or more of the antennas may be configuredto work with different wireless networks. Thus, for example, the antenna522A may be configured to transmit and receive signals over a 2Gnetwork, and the antenna 522B may be configured to transmit and receivesignals over a 3G network. In some cases, the antennas 522A and 522B mayboth be configured to transmit and receive signals over, for example, a2.5G network, but at different frequencies.

A number of other wireless device configurations can utilize one or morefeatures described herein. For example, a wireless device does not needto be a multi-band device. In another example, a wireless device caninclude additional antennas such as diversity antenna, and additionalconnectivity features such as Wi-Fi, Bluetooth, and GPS. Further, thewireless device 500 may include any number of additional components,such as analog to digital converters, digital to analog converters,graphics processing units, solid state drives, etc. Moreover, thewireless device 500 can include any type of device that may communicateover one or more wireless networks and that may include a number of FEMs540 which may share an integrated DC-DC supply regulator. For example,the wireless device 500 may be a cellular phone, including a smartphoneor a dumbphone, a tablet, a laptop, a video game device, a smartappliance, etc.

FIG. 6 illustrates a block diagram of another wireless device 600including a number of front-end modules 604 that share a DC-DC supplyregulator integrated in a 3G front-end module 620. The wireless device600 includes a number of the same elements as the wireless device 500.Further, as illustrated in FIG. 6, the FEMs 604 of the wireless device600 may include a number of FEMs. The FEMs 604 may include a 2G FEM 610,a 3G FEM 620, and a 4G FEM 612. In the illustrated example, the 3G FEM620 may include a DCDC+ Bias block 622, which may include a combinedDC-DC supply regulator and a bias circuit for supplying a bias currentto one or more power amplifiers included by the FEMs 604. The DCDC+ Bias622 may be in electrical communication with the 2G FEM 610 and the 4GFEM 612.

As illustrated by the dashed lines, the 2G FEM 610 may be optional insome embodiments. In such cases, the DCDC+ Bias 622 may be sharedbetween the 3G GEM 620 and the 4G FEM 612.

Terminology

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The term “coupled” is used to refer tothe connection between two elements, the term refers to two or moreelements that may be either directly connected, or connected by way ofone or more intermediate elements. Additionally, the words “herein,”“above,” “below,” and words of similar import, when used in thisapplication, shall refer to this application as a whole and not to anyparticular portions of this application. Where the context permits,words in the above Detailed Description using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, that word coversall of the following interpretations of the word: any of the items inthe list, all of the items in the list, and any combination of the itemsin the list.

The above detailed description of embodiments of the inventions are notintended to be exhaustive or to limit the inventions to the precise formdisclosed above. While specific embodiments of, and examples for, theinventions are described above for illustrative purposes, variousequivalent modifications are possible within the scope of theinventions, as those skilled in the relevant art will recognize. Forexample, while processes or blocks are presented in a given order,alternative embodiments may perform routines having steps, or employsystems having blocks, in a different order, and some processes orblocks may be deleted, moved, added, subdivided, combined, and/ormodified. Each of these processes or blocks may be implemented in avariety of different ways. Also, while processes or blocks are at timesshown as being performed in series, these processes or blocks mayinstead be performed in parallel, or may be performed at differenttimes.

The teachings of the inventions provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

Conditional language used herein, such as, among others, “can,” “might,”“may,” “e.g.,” and the like, unless specifically stated otherwise, orotherwise understood within the context as used, is generally intendedto convey that certain embodiments include, while other embodiments donot include, certain features, elements and/or states. Thus, suchconditional language is not generally intended to imply that features,elements and/or states are in any way required for one or moreembodiments or that one or more embodiments necessarily include logicfor deciding, with or without author input or prompting, whether thesefeatures, elements and/or states are included or are to be performed inany particular embodiment.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A front-end module for use in a wireless device,the front-end module comprising: a first power amplifier on anintegrated circuit die of the front-end module; and an integrated directcurrent to direct current converter circuit at least partially withinthe front-end module and located on the integrated circuit die, theintegrated direct current to direct current converter including acapacitor and an inductor external to the front-end module and connectedto a regulated supply output pin of the integrated circuit die, theintegrated direct current to direct current converter configured toregulate a first supply voltage provided to the first power amplifierand to regulate a second supply voltage provided to a second poweramplifier via the regulated supply output pin, the second poweramplifier located on a second integrated circuit die of a separatesecond front-end module not having a direct current to direct currentsupply regulator integrated on the second integrated circuit die.
 2. Thefront-end module of claim 1 wherein the second front-end module isconfigured for non-second generation cellular communication.
 3. Thefront-end module of claim 1 wherein the front-end module is configuredfor second generation cellular communication.
 4. The front-end module ofclaim 1 further comprising a switch configured to supply a signal fromthe first power amplifier to an antenna.
 5. The front-end module ofclaim 1 further comprising a bias circuit on the integrated circuit diecombined with the direct current to direct current converter circuit,the bias circuit configured to supply a bias current to the first poweramplifier.
 6. The front-end module of claim 1 wherein the capacitor andinductor form part of a bias circuit of the direct current to directcurrent converter circuit that regulates the second supply voltagesupplied to the second power amplifier.
 7. The front-end module of claim1 further comprising a third power amplifier configured to provide lowband second generation cellular communication and to receive power froma source and not the direct current to direct current converter circuit.8. The front-end module of claim 1 wherein the integrated direct currentto direct current converter circuit regulates voltage based on a voltagereceived from a power source.
 9. The front-end module of claim 1 furthercomprising one or more impedance matching networks configured to matchan impedance value of the first power amplifier to an impedance value ofan antenna.
 10. A method of regulating power supplied to a first poweramplifier and second power amplifier from an integrated direct currentto direct current converter circuit, the method comprising: regulating afirst power supply voltage by an integrated direct current to directcurrent converter circuit, the first power supply voltage provided to afirst power amplifier on an integrated circuit die of a front-endmodule, the integrated direct current to direct current convertercircuit having at least a portion within the front-end module located onthe integrated circuit die, and the direct current to direct currentconverter circuit having a capacitor and an inductor positioned externalto the front-end module and connected to a regulated supply output pin;and regulating a second power supply voltage by the integrated directcurrent to direct current converter circuit, the second power supplyvoltage provided to a second power amplifier located on a secondintegrated circuit die separate from the integrated circuit die and nothaving a direct current to direct current supply regulator configured onthe second integrated circuit die, the second power supply voltageprovided to the second power amplifier via the regulated supply outputpin of the integrated circuit die.
 11. The method of claim 10 whereinthe front-end module is configured for second generation cellularcommunication and the second front-end module is configured fornon-second generation cellular communication.
 12. The method of claim 10further comprising supplying a signal from one of the first poweramplifier and the second power amplifier to an antenna using a switch.13. The method of claim 10 further comprising supplying a bias currentto the first power amplifier from a bias circuit within the front-endmodule and combined with the direct current to direct current convertercircuit located on the integrated circuit die.
 14. The method of claim13 wherein the capacitor and inductor although external to the front-endmodule form part of the bias circuit of the direct current to directcurrent converter circuit.
 15. The method of claim 10 further providingpower to a third power amplifier configured to provide low band secondgeneration cellular communication, the power provided to the third poweramplifier provided from a power source that is not regulated by thedirect current to direct current converter circuit.
 16. The method ofclaim 10 wherein the integrated direct current to direct currentconverter circuit regulates voltage based on a voltage received from apower source.
 17. A multi-chip module comprising: a first front-endmodule implemented on a first integrated circuit die having a regulatedsupply output pin, the first front-end module including a first poweramplifier and at least a portion of an integrated direct current todirect current converter circuit configured to regulate a first supplyvoltage, the regulated first supply voltage provided to the first poweramplifier, and the direct current to direct current converter circuitincluding a capacitor and an inductor external to the front-end moduleand connected to the regulated supply output pin; and a second front-endmodule implemented on a second integrated circuit die that is separatefrom the first integrated circuit die and includes a second poweramplifier, the second power amplifier configured to receive a secondregulated supply voltage provided by the direct current to directcurrent converter circuit via the regulated supply output pin.
 18. Themulti-chip module of claim 17 wherein the second front-end module doesnot include a direct current to direct current converter circuitintegrated on the second integrated circuit die.
 19. The multi-chipmodule of claim 17 wherein the first front-end module includes a biascircuit within the front-end module and combined with the direct currentto direct current converter circuit, the bias circuit configured tosupply a bias current to the first power amplifier.
 20. The multi-chipmodule of claim 17 wherein the first front-end module includes a thirdpower amplifier that receives a supply voltage from a source other thanthe integrated direct current to direct current converter circuit, thefirst power amplifier configured to provide high band second generationcellular communication and the third power amplifier configured toprovide low band second generation cellular communication.